One Bit of Information About New Audio

by Jim Bray

The technically challenged among us may not know about 16 bit, 20 bit, 24 bit and all the other nifty and confusing audio bits, bytes, and samples that have been involved in the audio industry for the past twenty years, but despite that these computer terms have had a fundamental impact on the way we listen to music.

And now there’s another technology on tap that actually takes digital audio to its most fundamental basics.

Well, kind of, anyway. It’s called one-bit technology, which at least so far is mostly used in high-end audio systems and home theaters - though that may be about to change.

One-bit technology is supposed to combine the best of “old fashioned” analogue we knew from the vinyl record and cassette tape days (i.e., its fidelity to the original sound source) with digital technology’s virtually degradation-free transmission process.

Here’s how it works, in a non-technical nutshell:

The PCM (Pulse Code Modulation) technology of “old style” CD's records and reproduces audio frequencies from 20Hz up to 20kHz, which is approximately the audible range for humans. But the human ear can actually perceive sounds above 20kHz (depending on how much Rock and Roll has been listened to over the years!), and it’s said that some sounds in the natural world around us can reach of up to 100kHz. This is why dogs hear sounds we don’t: their ears have a different frequency range than humans.

And human children seem to have a hearing range much less than their parents, judging by how they act when spoken to by those parents. Oh wait, that isn’t a hearing range, it’s a listening range… You would think with the way kids act today that they need a hearing aid, but their behavior is more selective hearing than anything else.

But I digress…

One-bit audio is theoretically capable of achieving a frequency response of 0 to 100,000 hertz with a dynamic range (the ratio between the quietest and the loudest sounds a piece of equipment can reproduce) of 120 decibels. This is said to allow for the faithful reproduction of, for example, the “ca-ching” of a high hat cymbal, while the broader dynamic range can capture a full orchestra in all its glory.

To record and reproduce this full range of sounds, one-bit technology “samples” (takes a “digital picture of”) the original signal at what almost seems an unbelievable frequency: 2,822,400 times per second (2.8224MHz). That’s even faster than the sampling that goes on in the food section at Costco at lunchtime on a Saturday! In fact, it’s 64 times faster than a PCM CD’s sampling rate of 44.1kHz.

The other major factor in one-bit’s supposed superiority is its ability to eliminate signal deterioration, which means the sound stays true from recording right through playback in your home - theoretically of course. It does this by calculating only the differences between the samples, in effect comparing one sample with the next and ignoring the parts that don’t change. This is kind of similar to how DVD’s work: storage space is optimized by eliminating redundant information between one video frame and the next.

Sharp Electronics, among others, is bullish on one-bit technology, claiming that it finally realizes the dream of completely authentic sound reproduction. Okay, we’ve heard that before (I remember being told the same thing when the audio compact disc was introduced – and perhaps before that with “half speed master recordings” in the old vinyl days) but, despite the hype, one-bit audio technology sounds pretty nifty.

Then again, a friend of mine who co-owns a local high end audio store isn’t impressed, and I respect this person’s knowledge, so best to let your ears be the judge.

One bit goes beyond merely being a new recording medium: it’s opening up new markets for digital amplifiers as well as disc players. So if it lives up to its potential (and, as I’ve said, this is still a big “if”) it could help breathe new wind into your home audio system’s sails.

Time will tell, of course.

When applied to an amplifier, one bit technology can allow for a smaller footprint than traditional amps (which means it takes up less space), as well as supposedly being more energy efficient.

How much smaller and more efficient? When compared to a conventional amplifier of equivalent power output, a 1-bit amplifier only uses about half the energy and only radiates about a fifth as much heat. This allows a 1-bit amplifier to shrink to about a third the size of a conventional amplifier.

The downside is that your customers will no longer be able to toast marshmallows over their amps’ heat sinks!

Not surprisingly, early examples of one-bit technology tended to be high end and priced accordingly. Super Audio CD players, which use one bit technology, were anything but mainstream until recently as were one-bit amps. This may be changing.

Sharp Electronics, for example, has introduced a couple of interesting one-bit products, including the “all in one” SD-AT100, which not only has a 5.1 channel one-bit amplifier but which also includes a built-in DVD-CD, digital tuner and comes with a speakers. This system sells for about $1500, which is a pretty mainstream price considering the technology. Unfortunately, it doesn’t play SACD or DVD-Audio discs, which seems to defeat the purpose somewhat.

So is one-bit audio the Next Big Thing? Who knows? I haven’t even heard it yet (though I’ve heard SACD played back beautifully on a high end, conventional audio system), so can’t judge fairly how much is hype and how much is hope.

But it’s always nice to have choices. So if nothing else, one-bit audio is a welcome player.

Jim Bray's technology columns are distributed by the TechnoFILE Syndicate. Copyright Jim Bray.

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